Pressure responsive door latch actuator



ATTQRNEYS March 26,-1957 R. o. WRIGHT PRESSURE RESPONSIVE DooR LATCH AcTUAToR Filed March 8, 1952 PRESSURE RESPONSIVE DOOR LATCH ACTUATOR Raymond O. Wright, Healdsburg, Calif.

Application March 8, 1952, Serial No. 275,537

1 Claim. (Cl. 292-336.3)

This invention relates to door latches and particularly door latches which are selectively responsive to the degree of thrust applied and are accordingly inoperative by persons of impaired or undeveloped physical faculties;

In a great many cases it is highly desirable that door latches may not readily be operated by persons of impaired faculties or of mental and or physical immaturity yet that such latches are instantly operable by mature and unimpaired persons. Such is the case when it is desired to retain children or invalids within a limited area while permitting access by older persons or custodial personnel.

In general with cases of this nature physical capabilities as well as muscular coordination is considerably inferior to that of a normal or adult person. Accordingly the present invention provides a door latch actuator which is spring biased in a selectively inoperative position but which may be readily urged into an operative position by means of either a pushing or pulling thrust of a person of normal adult faculties approaching from either side of the door.

Therefore it is an object of this invention to provide a selectively pressure responsive door latch actuator which may not be operated by children or other persons of undeveloped or impaired physical faculties yet which is readily operable by a normal person.

Another object of this invention is to provide a door latch actuator in which an actuating member is retained in a spring-biased inoperative position.

Still another object of this invention is to provide a door latch actuator in which a rotative latch engagement member is retained in a normally inoperative position by a biasing force supplied by opposing springs which biasing force may be selectively disturbed in either direction by a relatively strong push or pull to engage the rotative member and actuate the door latch.

The invention possesses other objects and features of advantage, some of which, with the foregoing, will be set forth in the following description of the preferred form of the invention which is illustrated in the drawing accompanying and forming part of the specification. It is to be understood however, that variations in the showing made by said drawing may be adopted within the scope of the invention as set forth in the claim.

With reference to said drawing:

Figure l is a vertical transverse cross sectional view of a door latch assembly illustrating the installation of the door latch actuator of the invention;

Figure 2 is view taken along the plane 2-2 of Figure l illustrating details of the rotative engagement member of the selective door latch actuator.

At the outset it is to be noted that the latch actuator of this invention is intended primarily for use with any of the conventional door latch or bolt mechanisms in which a rotated member causes a spring loaded operating member to disengage a striker plate mounted in the door frame thereby allowing the door to be swung open. Many variations of this basic method have been employed, however, it is considered that the present actuator nited States Patent O ice may be appropriately applied to any such latch or bolt mechanism which includes a rotated, bolt operating member.

With reference to Figure l of the drawing there is illustrated a portion 10 of a conventional door panel in the latch area which door panel portion has been provided with a mortised opening 11 extending inwardly from the free edge thereof, in the customary manner, to receive a latch or bolt mechanism not shown.

Further in the usual manner there is provided in the door panel portion 10 axially aligned perforations` 12 and 13 extending transversely outwardly through the door panel portions 14 and 15 remaining between the mortise sides and surfaces 16 and 17 of said panel portion 10.

Disposed within said mortise 11, between the axially aligned perforations 12 and 13, there is shown a conventional rotatable member 18 which upon rotation causes sliding disengagement of a spring-loaded member as noted above. For purposes of illustration, such member generally may be considered to include a transverse, centrally located bore 19 in axial alignment with the perforations 12 and 13 and which bore is formed with a non-cylindrical configuration adapted for rotative engagement by a transversely displaced member of the actuator to be described hereinafter.

It will be appreciated that the possible appropriate configurations of said bore may include any variety of non-circular, toothed for other meshing or locking configuration which may be slidably engaged by said actuator member.

Generally indicated at 20, the transverse pressure responsive door latch actuator of this invention includes escutcheon plates 21 and 22 which may be attached to` door panel surfaces 16 and 17, respectively, so that the cylindrically perforated bushing members 23 and 24, respectively, provided in centrally disposed, transverse cylindrical perforations formed in said plates, are mutually disposed in axial alignment with the axially aligned door panel perforations 12 and 13 and the bore 19 of the rotatable bolt operating member 18.

With such an axial alignment of the said cylindrical perforations in the bushing members 23 and 24 with the bore 19, an elongated actuator engagement spindle member 25 may be inserted therethrough so as to extend beyond each of the panel surfaces 16 and 17 whereby threaded terminal portions 26 and 27 thereof may be provided with screwed-on door knobs 28 and 29, respectively, which are retained thereon by set screws 30. More particularly, the unitary member 25 includes a diametrically constricted central portion 31 adapted for free rotation within the bore 19 of the bolt operating member 18. Also included are intermediate portions 32 and 33 extending symmetrically outwardly from each side of said constriction to terminate in the threaded terminal portions 26 and 27, of the said member 25, respectively. The intermediate portions 32 and 33 are suitably shaped to correspond with the configuration of bore 19 being thereby adapted to slideably engage the rotated member 18 in mutually rotatable relation.

For example, as may best be seen in Figure 2, the intermediate portions 32 and 33 may be provided with a toothed or meshing conformation, which slideably engages a corresponding configuration of the bore 19, however, other meshing configurations and conformations are obviously equally applicable.

Completing the actuator 20, are compression springs 34 'and 35 which encircle intermediate portions 32 and 33,

respectively, in the lengths thereof located between the bushings 23 and 24 and knobs 28 and 29, respectively. Such compression springs 34 and 35 bear upon the respective knobs and bushings in such a manner that the constricted portion 31 of the actuator engagement member 25 is forciblyv biased in a central, mutually-disengaged, restposition' withinV the bore 19 of the rotative bolt operating member 18.

Accordingly in this position, rotation of the knobs cann'ot cause rotation of the rotative bolt operating member 15; However, when a push or pull thrust force is applied to either of the knobs, there is caused a transverse sliding displacement of the engagement member 25 with respect'to member 18 and consequent mutual engagement therewith, whereby rotation of the knobs will then cause rotation of' the bolt operating member i8, Consequently, the bolt of the door latch is actuated allowing the door to be opened.

It will now be apparent that judicious selection of the compressive strength of the compression springs provides a selective means of limitingthe operability of the door latch actuator to mature persons orthose of normal physical faculties, thereby' accomplishing the aims of the invention.

What is claimed is:

' A pressure responsive door latch actuator for use in combination with a latch having a rotatable bolt operating member provided with an axial bore of non-cylindrical configuration comprising a rotatable spindle member extending through said bore, said spindle member having a substantially cylindrical central portion adapted for free rotation in said bore and portions extending outwardly from said central portion having a cross-sectional form substantially the same as that of said bore, said portions extending outwardly from the central portion being axially spaced apart a distance at least equal to the axial length of said bolt operating member spaced bushing means for rotatably journalling said outwardly extending portions and permitting axial movement therebetween, knobs attached to terminal portions of said spindle member, and equal spring means disposed between each of said bushings and'itsradjacent knob for positioning said spindle member centrally with said central portion freely rotatable in said bore, said spindle member upon axial movement thereof against one of said spring means posi tioning .one of said outwardly extending portions in said bore whereby rotation of said spindle member will rotate said bolt operatingmember'.

References Cited in the le of this patent UNITED STATES PATENTS 351,107 Hickset al. Oct. 19, 1886 474,519 Candee May 10, 1892 855,177 Jack May 28, 1907 1,169,659 Lowell Jan. 25, 1916 1,968,285 Egan July 31, 1934 2,046,342 Muck et al July 7, 1936 FOREIGN PATENT SA 7,045 Great Britain Apr. 5, 1893 171,565 Great Britain Nov. 24, 1921 

